The present invention relates to the monitoring, and more particularly, to a monitor that is interposed between first and second digital equipment that exchanges digital information therebetween and the monitor is magnetically coupled to and routes the exchangeable digital information to means for capturing, recording, and analyzing the routed digital information.
An increasing complexity of computerized systems has created a need for a concomitant developmental engineering evaluation equipment for monitoring computer interfaces, such as the interfaces found in military installations that employ a Naval Tactical Data System (NTDS) protocol. The NTDS protocol comprises serial and parallel transmission techniques conforming to military specifications, such as military standard, input/output interfaces, standard digital data, Navy systems, MIL-Standard-1397C, herein incorporated by reference and which defines and describes the parameters of the Naval Tactical Data System (NTDS) interfaces which are of particular importance to the present invention. Systems which meet the requirements of military specifications are known and one such system is described in U.S. Pat. No. 5,661,583, which is herein incorporated by reference.
A NTDS interface which is of particular importance to the present invention is the NTDS Type E interface. The Type E interface consists of two digital equipment, one designated as an output function (source) and the other designated as an input function (sink). The source is that end of the Type E interface which transmits informational frames (IFs). The sink is that end of the Type E interface which receives IFs. Both the sink and the source are capable of transmitting and receiving control frames. The Type E interface transfers IFs from the source to the sink after the exchange of control frames. The NTDS Type E interface is more fully described in MIL-Standard-1397C.
A monitoring activity commonly involved with a NTDS Type E interface may be conducted for such practices as verifying proper computer control of a sensor, developing algorithms for data processing, verifying system performance, and other tasks related to computerized system development, acceptance, or improvement. The physical parameters of the environment in which the monitoring activity is conducted, especially for NTDS interfaces, varies from a relatively benign laboratory setting to the more severe shipborne embedded installations. Similarly, the range of cost factors that accompanies the monitoring activity varies from the relatively inexpensive laboratory testing to the expensive and critical data collection missions aboard a Navy vessel.
The monitoring activity typically involves routing digital data under consideration to means for capturing, recording and analyzing the digital data, such as that described in U.S. Pat. No. 5,614,896 which is herein incorporated by reference. This capturing, recording and analyzing means is commonly referred to as an instrumentation system, which terminology is used herein.
Various attempts to provide equipment for monitoring the activity for a NTDS interface have been made, but each suffered a shortcoming with respect to disturbing the interface or computerized system under the test. One such attempt that does not involve any hardwired interface between the involved equipment, but rather is handled by providing a dedicated output channel of the computerized equipment being monitored and analyzed. The dedicated channel provides associated output digital information directly to the instrumentation system. This approach is expensive in that it consumes a data channel of the computerized equipment being analyzed. It is desired that means be provided for routing the data being exchanged over a digital interface, especially a NTDS Type E interface, between first and second digital equipment to an instrumentation system without consuming a dedicated data channel of either of first or second digital equipment under analysis.
The present invention is directed to a monitor interposed between first and second digital equipment and routing the information exchanged between the first and second digital equipment to an instrumentation system, without causing any disruption of the digital data and without the consuming of a dedicated data channel of either of the first or second digital equipment under analysis.
The monitor is interposed between the first and second digital equipment that communicate with each other by digital signals in accordance with a first protocol. The first and second equipment have respective first and second connectors and conductors for carrying respective digital signals. The monitor has a ground connection that is magnetically isolated from a ground connection of an instrumentation system. The monitor comprises a directional coupler having an output and an input connected to the first and second connectors. The directional coupler directs and allows the digital signals of the first digital equipment to pass to its output and, conversely, inhibits the digital signals of the second digital equipment from passing to its output. The monitor further comprises an isolation coupling transformer having an input stage to receive the digital signals at the output of the directional coupler and an output stage connected to the instrumentation system.
Accordingly, it is a primary object of the present invention to provide a monitor for routing the digital information being exchanged over an NTDS interface, such as the NTDS Type E interface, to an instrumentation system and to also provide isolation between the instrumentation""s system ground and the monitor""s ground.
It is a further object of the present invention to isolate the monitor and instrumentation system grounds by the use of a high frequency coupling transformer so as to satisfy the requirements of a NTDS type E interface.
It is another object of the present invention to provide a monitor for routing information to an instrumentation system while at the same time preserving the controlled impedance of the NTDS interface being monitored.
It is another object of the present invention to provide for a monitor that creates little if any noise that might be reflected back onto the NTDS interface being monitored.
Furthermore, it is an object of the present invention to provide for a monitor that may be located at a relatively long distance from the instrumentation system so as to accommodate the needs of the instrumentation system""s shipborne environment.
Another object of the present invention is to provide for a monitor that does not delay the data being transferred between the equipment (source and sink) at either end of the NTDS Type E interface.
It is a further object of the present invention to provide a monitor that is adaptable to the NTDS Type E interface in that allows the monitor to relay data from the source NTDS equipment to the instrumentation system and inhibit data from the sink NTDS equipment from reaching the instrumentation system.
Other objects, advantages and novel features of the invention will become apparent from the following detailed description when considered in conjunction with the accompanying drawings therein.